package com.googlecode.carlosmonterocanabal.mojosprites;

import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

public class FileUtils {

    /**
     * Recursively walk a directory tree and return a List of all
     * Files found; the List is sorted using File.compareTo().
     * 
     * @param aStartingDir
     *            is a valid directory, which can be read.
     */
    static public List<File> getFileListing(File aStartingDir) throws FileNotFoundException {
        validateDirectory(aStartingDir);
        List<File> result = getFileListingNoSort(aStartingDir);
        Collections.sort(result);
        return result;
    }

    // PRIVATE //
    static private List<File> getFileListingNoSort(File aStartingDir) throws FileNotFoundException {
        List<File> result = new ArrayList<File>();
        File[] filesAndDirs = aStartingDir.listFiles();
        List<File> filesDirs = Arrays.asList(filesAndDirs);
        for (File file : filesDirs) {
            result.add(file); // always add, even if directory
            if (!file.isFile()) {
                // must be a directory
                // recursive call!
                List<File> deeperList = getFileListingNoSort(file);
                result.addAll(deeperList);
            }
        }
        return result;
    }

    /**
     * Directory is valid if it exists, does not represent a file, and can be read.
     */
    static private void validateDirectory(File aDirectory) throws FileNotFoundException {
        if (aDirectory == null) {
            throw new IllegalArgumentException("Directory should not be null.");
        }
        if (!aDirectory.exists()) {
            throw new FileNotFoundException("Directory does not exist: " + aDirectory);
        }
        if (!aDirectory.isDirectory()) {
            throw new IllegalArgumentException("Is not a directory: " + aDirectory);
        }
        if (!aDirectory.canRead()) {
            throw new IllegalArgumentException("Directory cannot be read: " + aDirectory);
        }
    }

    public static boolean removeDirectory(File directory) {

        // System.out.println("removeDirectory " + directory);

        if (directory == null)
            return false;
        if (!directory.exists())
            return true;
        if (!directory.isDirectory())
            return false;

        String[] list = directory.list();

        // Some JVMs return null for File.list() when the
        // directory is empty.
        if (list != null) {
            for (int i = 0; i < list.length; i++) {
                File entry = new File(directory, list[i]);

                // System.out.println("\tremoving entry " + entry);

                if (entry.isDirectory()) {
                    if (!removeDirectory(entry))
                        return false;
                } else {
                    if (!entry.delete())
                        return false;
                }
            }
        }

        return directory.delete();
    }

}
